<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>表格</title>
</head>
<body>
  <table border="1" cellpadding="10">
      <caption>学生信息表</caption>
      <thead>
        <tr>
            <th>序号</th>
            <th>姓名</th>
            <th>年龄</th>
            <th>身高</th>
        </tr>
      </thead>
      <tbody>
       <tr>
           <th>1</th>
           <td>张三</td>
           <td>18</td>
           <td>180</td>
       </tr>
       <tr>
           <th>2</th>
           <td>李华</td>
           <td>17</td>
           <td>188</td>
       </tr>
      </tbody>
      <tfoot>
        <tr>
            <td>平均年龄</td>
            <td colspan="3">17.5</td>
        </tr>
      </tfoot>
  </table>
</body>
</html>